Shield for water and sound

ABSTRACT

A composite high density plastic sheet, comprising a thermoplastic elastomer filled in substantial amount with an inorganic material, and intimately blended with a high strength low density polyethylene or elastomeric polymer whereby to provide one product the benefits of sound attenuation as well as inhibiting water and dust entry. The sheet can be cold-formed to include a pocket portion for use in applications such as receiving vehicle apparatus. Provision of a separate layer of the low density polyethylene assists in the sheets being stacked and adhesive permits the sheet to be removably attached to a surface of the apparatus.

RELATED APPLICATIONS

This is a continuation of U.S. Ser. No. 08/803,985, filed Feb. 21, 1997,now U.S. Pat. No. 6,045,921, which is a continuation-in-part of U.S.Ser. No. 08/391,407, filed Feb. 16, 1995; which is a divisional of U.S.Ser. No. 08/160,375, filed Nov. 30, 1993, now U.S. Pat. No. 5,409,779;which is a continuation of U.S. Ser. No. 07/652,021, filed Feb. 7, 1991,now abandoned.

BACKGROUND OF THE INVENTION

This invention is directed to a composite, high density plastic sheetmaterial used in the manufacture of a water, dust, wind, air and soundbarrier and method of making same. The invention is particularly suitedfor use in the manufacture of automotive vehicle door panels and will bedescribed with reference thereto, however, as will become apparent, theinvention is capable of broader application and could equally well beused as a lightweight sound barrier shield or vibration dampener.Another aspect of the present invention is directed to a sound barrierfor use in construction of a building.

It is known that surface protectors or deflectors are particularlysuited for shielding the inner panels of vehicles against theinfiltration of water or dust. In general, the deflectors comprise athin, flexible sheet of a plastic material having a peripheral shape tooverlie a predetermined portion of the inner door sheet metal.Typically, the deflectors are joined to the door sheet metal by pressuresensitive adhesive applied in a band around the peripheral edge of thedeflectors.

There has been an ongoing need for the flat deflectors to include bulgesor pockets to allow them to adequately accommodate radio speakers, doorpanel clips and similar devices which extend inwardly or outwardly ofthe door from the inner panel. Typically, the sheet results from athermoforming operation. These prior attempts have not been altogethersuccessful, especially when the sheet must be cured, stacked, andprovided with the adhesive.

Further, the plastic deflectors have not been altogether satisfactory inpreventing noise transmission (e.g., tire noises).

Additionally, while many types of insulation materials are available forhome use, there remains a need for a sound deadening material which canbe easily applied to building structures for providing sound deadening.

The subject invention provides a structure and method of forming thesame which overcome the above-noted problems and others in an economicalmanner.

SUMMARY OF THE INVENTION

In accordance with the subject invention, a suitable barrier againstwater, sound, dust and air comprises a mixture of an inorganicallyfilled thermoplastic elastomer intimately blended with a suitablepolyethylene, such as those characterized as being a low densitypolyethylene (LDPE), or a linear low density polyethylene (LLDPE), anultra-low density polyethylene (ULDPE), or an elastomeric thermoplastic.In accordance with one aspect of this invention, the barrier is eithercold formed or hot formed to include a bulge or pocket like area. Inaccordance with another aspect of this invention, the barrier is formed(e.g., laminated) to include a separate layer of a low surface energypolymer, such as the low density polyethylene, or treated with siliconerelease coating, whereby the barriers can be stacked for dispensing. Inaccordance with yet another aspect of the invention, the barrier canform a deflector against sound and water.

In an alternate embodiment the subject invention may be used in a systemfor sound deadening a room. The barrier is provided in a thickerrotatable form. The system may include attaching this film to eitherwall structures or to a wallboard or other wall covering material whichcan be secured to the wall framework.

Advantageously, the barrier can be formed by a single extrusion orco-extrusion processes that are known in the art and thus allowing theuser to utilize known forming techniques and apparatus.

A further advantage is provision in one product the sound, water, dust,air, wind, ease of installation, and cost benefits.

A further advantage is provision of a composite sheet which is not onlyflexible but also somewhat limp, whereby to deaden sound transmissionloss in both the low as well as the high frequency ranges. Although thecomposite sheet is relatively flexible, it is still sufficiently rigidto function as a barrier but the limp nature of the sheet minimizesvibration of its own thereby preventing harmonic vibration such as thatcaused by speakers.

A further advantage is provision of a barrier of the type describedhaving a plurality of pockets or bulges for use in vehicle door panelswherein the user utilizes the bulges to position the barrier on the doorduring installation.

A further advantage is providing a construction sound attenuationbarrier for use in buildings, and a method for sound deadening a room byusing barriers with preformed pockets for deadening around outlets orthe like.

Advantageously, the bulge can be cold-formed whereby post curingdifficulties are obviated. Desirably so, such as where the bulge issomewhat cone-shaped, the material thickness can be maintained ofgenerally uniform thickness and does not tend to have thinned regions ofreduced strength.

The above and other advantages of the invention will become apparent tothose skilled in the art upon a reading and understanding of thefollowing description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a barrier of the present inventionfor application to an automotive vehicle door.

FIGS. 2(a) and 2(b) are cross-section views showing the cold-forming ofa pocket in the barrier of FIG. 1.

FIG. 3 is a perspective and elevational view partially in phantomshowing the sound barrier application structure.

FIG. 4 is a sectional view taken along line 4—4 of FIG. 3.

FIG. 5 is a sectional view showing a wallboard sound barrier laminate.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Turning now to the drawings, a barrier according to the presentinvention for inhibiting passage of water, sound, air and dirt will bedescribed with respect to its application to a vehicle door and willalso be described for applications involving sound barriers in buildingstructures.

In FIG. 1, a vehicle door is comprised of an outer metallic door frame10 having a plurality of spaced openings 12, an inner trim panel 14sized to fit onto and be secured to the frame, and a barrier 16cold-formed to include a plurality of bulges or pockets 18. Thearrangement and shape of the frame, panel and barrier would change,according to the vehicle model.

Barrier 16 is illustrated as comprising a generally thin planar sheetcomprised of a thermoplastic elastomer filled with a substantial amountof an inert or inorganic material intimately blended with a suitable lowdensity polyethylene (LDPE), including those plastics characterized asbeing a linear low density polyethylene (LLDPE), an ultra-low densitypolyethylene (ULDPE), or an elastomeric polymer. The thermoplasticelastomer comprises between 80% to 98% and preferably about 95% and thepolyethylene comprises between 2% to 20% and preferably about 5%, byweight. The thickness of the sheet is minimized and the flexibilitymaximized by the inorganic filler content comprising at least 50% toabout 85% of the thermoplastic elastomer, by weight, and preferably 80%,and the inorganic filler consisting essentially of calcium carbonate andbarium sulfate. Sound deadening benefits are achieved by theabove-subject thermoplastic elastomer. The water, wind, air and dustbenefits are achieved through the ability of the low densitypolyethylene to impart flexibility, high tear strength and stretchcharacteristics to the sheet. A decrease in tear strength of the barrierresults when the polyethylene approaches the lower end of its range. Onesuitable thermoplastic elastomer is Keldex® 6868, a trademark of DuPont,and one suitable low density polyethylene is Attane®, a trademark of DowChemical Company. Other polyethylenes which are suitable include olefinplastomers such as Affinity®, available from Dow Chemical Company,Midland, Mich.; and EXPOL® plastomers, available from Exxon, Houston,Tex., which have a density range of 0.870 to 0.930 gm/cc. A suitableexample is Affinity® PF 1140 olefin plastomer, available from DowChemical Company.

While those skilled in the art will recognize that the sheet could havedifferent thicknesses, for the intended purposes, it has been found thata thickness in the range of approximately 15-35 mils is preferable.Sound attenuation is directly proportional to the basis of the weight ofthe sheet. Generally, a weight basis of from about 0.15 to 0.75 lb./sq.ft. is used. A preferred weight basis is in the range of 0.15 to 0.30lb./sq. ft. Lighter weight basis sheets are suitable for some uses butfor proportionally lower sound attenuation.

In accordance with this invention, a layer 20 of the low densitypolyethylene (e.g., Attane®) can be formed on one surface or bothsurfaces of the sheet. Many methods are possible, such as lamination,co-extrusion or extrusion coating. These methods would be known to thoseskilled in the art.

In one embodiment, the composite barrier 16 was about 20 mils thick, andthe layer 20 was about 2 mils, making the total sheet thickness about 22mils. The cone 18 was about 2 inches in diameter and height. The densityof the thermoplastic elastomer was about 2.07 gm/cubic centimeters. Thedensity of the polyethylene was in the range of about 0.870 to 0.930gm/cubic centimeters, and preferably about 0.901 gm/cubic centimeters.

Referring now to FIGS. 2(a) and 2(b), the pockets or forms are shownbeing formed by a cold-forming drawing operation although otherconventional techniques could be utilized, such as vacuum forming. FIG.1 shows the general configuration of a preferred pocket 18 as beingcone-shaped. In the drawing operation, cooperating interengaging diemembers 22 and 24 are moved together with the composite sheet comprisingbarrier 16 and layer 18 positioned therebetween. The die members arethen moved toward one another to produce localized stretching andpermanent deformation of the sheet. The pocket 18 can advantageously beformed in the sheet while the sheet is at or near room temperature andwithout the use of thermoforming equipment. The process allowsconventional presses to be used for both pocket forming and sheetcutting. The choice of materials allows the pocket to form withoutmemory and tearing, due to the high tear and elongation properties ofthe composition materials. The pocket is collapsible to lie essentiallyin the plane of the sheet and extendable in a direction away from thesheet.

Additionally, if desired, a plurality of barriers 16 can be die cut andstacked without the use of a carrier or a release sheet. In this regard,relative ease of release between parts can be achieved through the useof a silicone release coating, or the co-extrusion of a low surfaceenergy polymer on one side. A preferred silicone release coating isGeneral Electric UV 9300, a 100% solid, ultraviolet cure coating, at asurface deposition of less than 1 gm/sq. m. A preferred low energypolymer is the above-mentioned Attane® or Affinity®, applied at asurface layer thickness of 1 to 3 mils, using standard lamination,co-extrusion or extrusion techniques.

In operation, the highly filled thermoplastic elastomer (e.g., Keldex®)and low density polyethylene (e.g., Attane®) or elastomeric polymer aremixed together in an extruder, intimately blended, formed into a sheet,and wound on a roll. If desired, the layer 20 of polyethylene could beformed simultaneously. This sheet material is then calendared to smoothout roughness. If desired, the sheet could be unwound, whereby toreceive the silicone layer, and a desired adhesive pattern, and thencured. The cone can be formed by passing the sheet between theinterengaging dies. Thereupon the cone-formed sheet could be rewound andsent to a die cutting machine. There the sheets would be cut, stacked,and die cut into a desired configuration, such as barrier 16. It shouldbe understood that some steps could be substantially simultaneous, suchas die cutting and cone forming and die cutting and sheet forming. Thesheet could be formed to include a plurality of pockets, depending onthe vehicle door. The pockets assist the user in assembly by supportingthe sheet on the door.

Additionally, the single sheet without pockets could be used toadvantage in non-automotive applications. The inorganically filledthermoplastic elastomer adds needed mass, which assists in deadeningsound. While the sound attenuation (i.e., sound transmission loss)improves at the higher frequencies (i.e., short wavelengths), benefitsare gained at the low frequencies (i.e., long wavelengths), such asoutside noise.

The composition of barrier 16 provides a limp elastic structure, asopposed to a thin sheet of a single plastic material, that assists indeadening sound. As such, the barrier can be applied to a metal plate asa vibration dampener or used as a sound barrier.

Referring now to FIG. 3, there is shown a sound deadening system whichis shown at 100. The system 100 includes a sound deadening material 102which may be applied to a wall structure 104. Wall structures such asshown at 104 include 2×4 or other framework and may include outlet boxessuch as shown at 106 or switch boxes such as shown 108.

The deadening material 102 is of the same composition generally as theautomotive barrier shield. However, the preferred embodiment for thesound barrier in the present invention is a blended mixture ofthermoplastic elastomer and polyethylene in the ranges set forth above.The product primarily differs in that for sound deadening in buildingsthe material is somewhat thicker than the automotive applications. Thethickness of the material may range generally from about 35 thousandthsof an inch up to 1 inch. Preferably, the material of the presentinvention has a thickness of from about 50 to 75 thousandths of an inchwhich allows the material to be rolled into rolls as shown in FIG. 3 toprovide an easy method of application of the material to the structure104. Preferably, the materials of the present invention have a soundtransmission factor (STF) of above 50. The material may be provided inrolls which are 48 inches wide such that they may be applied overstandard wall sizes in a horizontal direction.

In the system of the present invention, a preconfigured cut-out member110 having a surrounding indentation 111 is provided for applicationaround wall inserts such as outlet boxes or the like which requireinsulation from sound to provide a more secure sound deadeningarrangement. Thus, as shown in FIG. 4, a hole 112 may be cut in thematerial 102 and the insert member 110 would be placed within the holeand adhered by an adhesive layer 114 or may be stapled to the studs 116above. Thereafter, a suitable hole may be drilled through wire insertionand the box 106 may be applied to the stud as is known in the art.

In an alternate embodiment as shown in FIG. 5, the material of thepresent invention 102 may be laminated to a wallboard 118 or otherinsulating material. This provides a sound deadening material forbacking up the wallboard or the like thereby providing a very effectivesound barrier for construction building applications. Thus, the laminatepanels could be produced by laminating material to 4′×8′ sheets ofwallboard. Thereafter the 4′×8′ sheets could be placed on standard 16″center 2×4 wall frames as are known in residential construction. Soundbarriers of the present invention are effective since they are highlyfilled and create sound deadening above and beyond most standards.

The product can be used as a single layer, or also as a laminate withthe outer layer as disclosed previously. The sound barrier may belaminated on one side or both sides with a polyethylene, as may bedesired. Advantages of lamination, on either one or both sides, areimproved moisture resistance, improved barrier properties, and thepolyethylene layer allows adhesion as well as mechanical fastening forplacement of the barrier in structures or the like. Thus, depending onthe final desired properties, the sheet may have films on one side, orboth sides, to provide the proper barrier properties.

While the above description constitutes the preferred embodiment(s) ofthe invention, it. will be appreciated that the invention is susceptibleto modification, variation, and change without departing from the properscope or fair meaning of the accompanying claims.

What is claimed is:
 1. A barrier device consisting essentially of amixture of polyethylene or elastomeric polymer intimately blended with athermoplastic elastomer substantially filled with an inorganic filler,wherein said barrier device is substantially impervious to water and airand has enhanced sound deadening properties, wherein said barrier devicecomprises a substantially thin continuous planar sheet having first andsecond surfaces and an edge of desired configuration, and asubstantially thin continuous planar layer of low density polyethylenebeing formed on one of said surfaces.
 2. The invention as recited inclaim 1, wherein said thermoplastic elastomer comprises from about 80%to about 98% and said polyethylene comprises from about 2% to 20%, byweight.
 3. The invention as recited in claim 1, wherein thethermoplastic elastomer is about 95% and the polyethylene is about 5%,by weight.
 4. The invention as recited in claim 1, wherein the elastomerhas a weight basis in the range of 0.15 to 0.75 lb./sq. ft.
 5. Theinvention as recited in claim 1 wherein the inorganic filler comprisesbetween about 50% to about 85% of the thermplastic elastomer.
 6. Theinvention as recited in claim 1 wherein the inorganic filler comprisesat least about 50% of the thermoplastic elastomer.
 7. The invention asrecited in claim 1, wherein the inorganic filler comprises approximatelyabout 80% of the thermoplastic elastomer.
 8. The invention as recited inclaim 1 wherein the inorganic filler consists essentially of calciumcarbonate and barium sulfate, which have densities in the range of fromabout 1.0 to about 5.0 lbs./cu. ft.
 9. The invention as recited in claim1, further comprising a low energy polymer co-extruded on one of saidsurfaces.
 10. The invention as recited in claim 1, further comprising arelease agent bonded on one of said surfaces.
 11. The invention asrecited in claim 1, wherein said thin planar sheet further comprises atleast one pocket being formed therein, said pocket being collapsible tolie essentially in the plane of the sheet and extendible in a directionaway from one surface of said barrier.